Netflix reality show brought me here. The rumoured smelly helmet might somewhat true, though u can cover your hair with hotel's shower cap.
The trip from jogja to the cave might take some time, once u arrive - they will put you into a pulley to bring you down to the cave. As back then i came during the rainy season, the cave was really muddy. There was some pitch dark moment, so makd sure to bring your flashlight (or phone will do, thus it can get dirty as well).